so ithought always that keeping those NPCS alive is such a PAIN. so i added around 15 units to guard them ( mostly rangers,druids,paladins) also i increased their level so you have to build 20 towers around them.
also i added a computer ally by removing one player slot. Realm Level 2 they will attack very 7 minutes with around 20 troops max allowed is 50.
EDIT:i post the map tomorrow because strangely forum is in france for me and i dont have much figuring it out